/*!
 * Crypto-JS v1.1.0
 * http://code.google.com/p/crypto-js/
 * Copyright (c) 2009, Jeff Mott. All rights reserved.
 * http://code.google.com/p/crypto-js/wiki/License
 */
(function() {

  // Shortcut
  var util = Crypto.util;

  // Precomputed SBOX
  var SBOX = [0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
    0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
    0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc,
    0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
    0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
    0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b,
    0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
    0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
    0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17,
    0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
    0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
    0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9,
    0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
    0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
    0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94,
    0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
    0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16
  ];

  // Compute inverse SBOX lookup table
  for (var INVSBOX = [], i = 0; i < 256; i++) INVSBOX[SBOX[i]] = i;

  // Compute mulitplication in GF(2^8) lookup tables
  var MULT2 = [],
    MULT3 = [],
    MULT9 = [],
    MULTB = [],
    MULTD = [],
    MULTE = [];

  function xtime(a, b) {
    for (var result = 0, i = 0; i < 8; i++) {
      if (b & 1) result ^= a;
      var hiBitSet = a & 0x80;
      a = (a << 1) & 0xFF;
      if (hiBitSet) a ^= 0x1b;
      b >>>= 1;
    }
    return result;
  }

  for (var i = 0; i < 256; i++) {
    MULT2[i] = xtime(i, 2);
    MULT3[i] = xtime(i, 3);
    MULT9[i] = xtime(i, 9);
    MULTB[i] = xtime(i, 0xB);
    MULTD[i] = xtime(i, 0xD);
    MULTE[i] = xtime(i, 0xE);
  }

  // Precomputed RCon lookup
  var RCON = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36];

  // Inner state
  var state = [
      [],
      [],
      [],
      []
    ],
    keylength,
    nrounds,
    keyschedule;

  var AES = Crypto.AES = {

    /**
     * Public API
     */

    encrypt: function(message, password, mode) {

      var

        // Convert to bytes
        m = util.stringToBytes(message),

        // Generate random IV
        iv = util.randomBytes(AES._blocksize * 4),

        // Generate key
        k = Crypto.PBKDF2(password, util.bytesToString(iv), 32, {
          asBytes: true
        });

      // Determine mode
      mode = mode || Crypto.mode.OFB;

      // Encrypt
      AES._init(k);
      mode.encrypt(AES, m, iv);

      // Return ciphertext
      return util.bytesToBase64(iv.concat(m));

    },

    decrypt: function(ciphertext, password, mode) {

      var

        // Convert to bytes
        c = util.base64ToBytes(ciphertext),

        // Separate IV and message
        iv = c.splice(0, AES._blocksize * 4),

        // Generate key
        k = Crypto.PBKDF2(password, util.bytesToString(iv), 32, {
          asBytes: true
        });

      // Determine mode
      mode = mode || Crypto.mode.OFB;

      // Decrypt
      AES._init(k);
      mode.decrypt(AES, c, iv);

      // Return plaintext
      return util.bytesToString(c);

    },


    /**
     * Package private methods and properties
     */

    _blocksize: 4,

    _encryptblock: function(m, offset) {

      // Set input
      for (var row = 0; row < AES._blocksize; row++) {
        for (var col = 0; col < 4; col++)
          state[row][col] = m[offset + col * 4 + row];
      }

      // Add round key
      for (var row = 0; row < 4; row++) {
        for (var col = 0; col < 4; col++)
          state[row][col] ^= keyschedule[col][row];
      }

      for (var round = 1; round < nrounds; round++) {

        // Sub bytes
        for (var row = 0; row < 4; row++) {
          for (var col = 0; col < 4; col++)
            state[row][col] = SBOX[state[row][col]];
        }

        // Shift rows
        state[1].push(state[1].shift());
        state[2].push(state[2].shift());
        state[2].push(state[2].shift());
        state[3].unshift(state[3].pop());

        // Mix columns
        for (var col = 0; col < 4; col++) {

          var s0 = state[0][col],
            s1 = state[1][col],
            s2 = state[2][col],
            s3 = state[3][col];

          state[0][col] = MULT2[s0] ^ MULT3[s1] ^ s2 ^ s3;
          state[1][col] = s0 ^ MULT2[s1] ^ MULT3[s2] ^ s3;
          state[2][col] = s0 ^ s1 ^ MULT2[s2] ^ MULT3[s3];
          state[3][col] = MULT3[s0] ^ s1 ^ s2 ^ MULT2[s3];

        }

        // Add round key
        for (var row = 0; row < 4; row++) {
          for (var col = 0; col < 4; col++)
            state[row][col] ^= keyschedule[round * 4 + col][row];
        }

      }

      // Sub bytes
      for (var row = 0; row < 4; row++) {
        for (var col = 0; col < 4; col++)
          state[row][col] = SBOX[state[row][col]];
      }

      // Shift rows
      state[1].push(state[1].shift());
      state[2].push(state[2].shift());
      state[2].push(state[2].shift());
      state[3].unshift(state[3].pop());

      // Add round key
      for (var row = 0; row < 4; row++) {
        for (var col = 0; col < 4; col++)
          state[row][col] ^= keyschedule[nrounds * 4 + col][row];
      }

      // Set output
      for (var row = 0; row < AES._blocksize; row++) {
        for (var col = 0; col < 4; col++)
          m[offset + col * 4 + row] = state[row][col];
      }

    },

    _decryptblock: function(c, offset) {

      // Set input
      for (var row = 0; row < AES._blocksize; row++) {
        for (var col = 0; col < 4; col++)
          state[row][col] = c[offset + col * 4 + row];
      }

      // Add round key
      for (var row = 0; row < 4; row++) {
        for (var col = 0; col < 4; col++)
          state[row][col] ^= keyschedule[nrounds * 4 + col][row];
      }

      for (var round = 1; round < nrounds; round++) {

        // Inv shift rows
        state[1].unshift(state[1].pop());
        state[2].push(state[2].shift());
        state[2].push(state[2].shift());
        state[3].push(state[3].shift());

        // Inv sub bytes
        for (var row = 0; row < 4; row++) {
          for (var col = 0; col < 4; col++)
            state[row][col] = INVSBOX[state[row][col]];
        }

        // Add round key
        for (var row = 0; row < 4; row++) {
          for (var col = 0; col < 4; col++)
            state[row][col] ^= keyschedule[(nrounds - round) * 4 + col][row];
        }

        // Inv mix columns
        for (var col = 0; col < 4; col++) {

          var s0 = state[0][col],
            s1 = state[1][col],
            s2 = state[2][col],
            s3 = state[3][col];

          state[0][col] = MULTE[s0] ^ MULTB[s1] ^ MULTD[s2] ^ MULT9[s3];
          state[1][col] = MULT9[s0] ^ MULTE[s1] ^ MULTB[s2] ^ MULTD[s3];
          state[2][col] = MULTD[s0] ^ MULT9[s1] ^ MULTE[s2] ^ MULTB[s3];
          state[3][col] = MULTB[s0] ^ MULTD[s1] ^ MULT9[s2] ^ MULTE[s3];

        }

      }

      // Inv shift rows
      state[1].unshift(state[1].pop());
      state[2].push(state[2].shift());
      state[2].push(state[2].shift());
      state[3].push(state[3].shift());

      // Inv sub bytes
      for (var row = 0; row < 4; row++) {
        for (var col = 0; col < 4; col++)
          state[row][col] = INVSBOX[state[row][col]];
      }

      // Add round key
      for (var row = 0; row < 4; row++) {
        for (var col = 0; col < 4; col++)
          state[row][col] ^= keyschedule[col][row];
      }

      // Set output
      for (var row = 0; row < AES._blocksize; row++) {
        for (var col = 0; col < 4; col++)
          c[offset + col * 4 + row] = state[row][col];
      }

    },


    /**
     * Private methods
     */

    _init: function(k) {
      keylength = k.length / 4;
      nrounds = keylength + 6;
      AES._keyexpansion(k);
    },

    // Generate a key schedule
    _keyexpansion: function(k) {

      keyschedule = [];

      for (var row = 0; row < keylength; row++) {
        keyschedule[row] = [
          k[row * 4],
          k[row * 4 + 1],
          k[row * 4 + 2],
          k[row * 4 + 3]
        ];
      }

      for (var row = keylength; row < AES._blocksize * (nrounds + 1); row++) {

        var temp = [
          keyschedule[row - 1][0],
          keyschedule[row - 1][1],
          keyschedule[row - 1][2],
          keyschedule[row - 1][3]
        ];

        if (row % keylength == 0) {

          // Rot word
          temp.push(temp.shift());

          // Sub word
          temp[0] = SBOX[temp[0]];
          temp[1] = SBOX[temp[1]];
          temp[2] = SBOX[temp[2]];
          temp[3] = SBOX[temp[3]];

          temp[0] ^= RCON[row / keylength];

        } else if (keylength > 6 && row % keylength == 4) {

          // Sub word
          temp[0] = SBOX[temp[0]];
          temp[1] = SBOX[temp[1]];
          temp[2] = SBOX[temp[2]];
          temp[3] = SBOX[temp[3]];

        }

        keyschedule[row] = [
          keyschedule[row - keylength][0] ^ temp[0],
          keyschedule[row - keylength][1] ^ temp[1],
          keyschedule[row - keylength][2] ^ temp[2],
          keyschedule[row - keylength][3] ^ temp[3]
        ];

      }

    }

  };

})();
